The present invention relates to a structure of a battery box in which a dry battery is introduced and secured, and in particular, to a technology for preventing an accidental event resulting from a short-circuit condition of the dry battery.
There is a variety of electrical appliances driven by means of dry battery (batteries), and there is a variety type of battery box sections for receiving the dry batteries, which varies corresponding to the types of the dry batteries used in those electrical appliances.
On the one hand, typical dry batteries used for the electrical appliances include a manganese dry battery and an alkaline dry battery, and recently, the alkaline dry battery having a high capacity and an excellent discharge property at a high current has been commonly used in various fields. This alkaline dry battery is similar to the manganese dry battery in an external appearance and a size but more or less different from that in used material and structure.
In contrast to that the manganese dry battery is produced by filling a zinc can with various materials such as zinc chloride and neutral aqueous solution of ammonium chloride, which will be finally sealed with a tube referred to as a metal jacket, the alkaline dry battery is produced by filling an outer case referred to as a positive electrode can with electrolyte and separator prepared as the stuffs, sealing the can, and then wrapping around said can a label indicating a performance of the battery and/or a caution therefor.
As described above, in the alkaline dry battery the positive electrode can is wrapped with the label sheathing and this label sheathing is thin and apt to be torn. Especially, although the positive electrode can and a collector are sealed in their openings, there should be a recess in a connecting surface between them and thus a space created between the label sheathing and the connecting surface. Owing to this, a portion of interest defined in a lower region of the dry battery (at cathode side) has been more apt to be broken.
FIG. 5A is a sectional view showing a structure of a battery box according to the prior art, which comprises a positive electrode terminal 52 and a negative electrode terminal 53 each serving as contact in the left or the right side within the battery box 51. It is to be noted that this battery box is of a type in which two of the dry batteries are received longitudinally one after another.
Generally, to insert the dry batteries into this battery box 51, after first one of the dry batteries 12a has been fitted in the battery box in its positive electrode terminal side, a second one of the batteries 12b is inserted with its cathode side inclined downwardly, as shown in FIG. 5B. Alternatively, after the first one of the dry batteries 12b has been set in the battery box in its negative electrode terminal side, the second one of the dry batteries 12a may be set in the battery box from the positive electrode terminal side of the battery box, as shown in FIG. 5C. Once the batteries have been set by either of those setting methods described above, the setting of the dry batteries should be considered completed.
FIG. 6A shows a case where an erroneous inserting method has been applied to insertion of the alkaline dry batteries into the prior art battery box. As shown in this FIG. 6A, if the dry battery is to be inserted into the battery box 51 with the cathode side of the dry battery 12b lifted upwardly, a lateral face of the dry battery 12b could come into contact with the spring-shaped negative electrode terminal 53. At that time, if an additional force is applied to the dry battery 12b so as to push it into the battery box 51, the dry batteries could be received within the battery box 51 in the condition that the spring is deformed or collapsed as shown in FIG. 6B. If the hand is moved away from the battery under this condition, in most cases, the dry battery would pop out of the battery box 51 by the restoring force of the spring, but if the battery box has a lid and the lid is forced into its closed position under this condition with the spring deformed, then there would be a possibility that the dry batteries could have been housed in an improper state. This is an event that could possibly occur if a user is in a hurry to use the appliance.
If the dry batteries used in this case are the alkaline dry batteries, there is a possibility that a strong contact with the spring-shaped negative electrode terminal 53 made of metal would tear the label sheathing of the outermost layer, thereby bringing the positive electrode can inside thereof into a stripped-out condition. In this condition, if the spring comes into contact with the positive electrode can and the cathode of the dry battery at the same time, it would result in a short-circuit condition (a short). There is a fear that the short-circuit between both electrode terminals of the dry battery could not only reduce the operating life of the dry battery as commonly known well but also induce a heat developed inside thereof and/or a fluid leakage therefrom. There has been further possibility that such an accident may not simply induce a failure of the dry battery but may lead to the failure of the electrical appliances itself dependently on the case.
The present invention has been made in the light of the circumstance described above, and an object thereof is to provide a battery box which can prevent an erroneous insertion of a dry battery thereby avoiding a short-circuit condition thereof.
A battery box according to the present invention comprises a positive electrode terminal and a negative electrode terminal disposed in opposite ends in the longitudinal direction of a housing section, in which a contact preventing member is disposed in a location above at least one of said positive electrode terminal and said negative electrode terminal for preventing a lateral face of a dry battery to be inserted in the battery box from coming into contact with said at least one of said positive electrode terminal and said negative electrode terminal.
In a battery box according to the present invention, said contact preventing member is formed as a bridge section which is bridged across said housing section in the direction crossing the longitudinal direction of said housing section.
In a battery box according to the present invention, said contact preventing member is formed as a protrusion which is protruding toward an inside of said housing section in the direction crossing the longitudinal direction of said housing section.
Further, in a battery box according to the present invention, said contact preventing member extends only along a region proximal to a front end portion of said negative electrode terminal with respect to said longitudinal direction.
Further, in a battery box according to the present invention, said contact preventing member extends from a region proximal to a front end portion of said negative electrode terminal to a region proximal to an end portion of said housing section with respect to said longitudinal direction.
Still further, in a battery box according to the present invention, said contact preventing members are disposed on respective side walls in opposite sides of said housing section.
Further, in a battery box according to the present invention, said contact preventing member is disposed on a side wall in one side of said housing section.
Yet further, in a battery box according to the present invention, a degree of protrusion of one of the contact preventing members is different from the degree of protrusion of the other one of the contact preventing members.
A battery box according to the present invention further comprises a lid for covering said housing section and said lid has a through hole formed in such a location in which said contact preventing member can penetrate through said lid when the lid is closed.
Further, in a battery box according to the present invention, said at least one of said positive electrode terminal and said negative electrode terminal is the negative electrode terminal and said negative electrode terminal is formed in an elastically deformable spring-like shape.